The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	An improved method of gas chromatographic determination of trace organic vapors in ambient air collected in canisters
Author:	Shen, Yong-jin
View Online:	njit-etd1988-047 (vi, 58 pages ~ 2.0 MB pdf)
Department:	Department of Civil and Environmental Engineering
Degree:	Master of Science
Program:	Environmental Engineering
Document Type:	Thesis
Advisory Committee:	Kebbekus, Barbara B. (Committee chair) Bozzelli, Joseph W. (Committee member) Dauerman, Leonard (Committee member)
Date:	1988-05
Keywords:	Air -- Pollution -- Measurement Gas chromatography
Availability:	Unrestricted
Abstract:	An improved method for analysis and quantitation of volatile organic compounds in ambient air has been developed. Samples are collected in evacuated SUMMA polished stainless steel canisters using a sampling flow apparatus with a critical orifice as flowrate controller. Analysis of VOCs in the collected air is carried out by cryogenically concentrating the sample, then thermally transfering it onto the head of a capillary column in a gas chromatograph. The column effluent is measured by a parallel flame ionization detector (FID), and electron capture detector (ECD). The problems associating with quantitative transfer of the sample to the initial cryofocusing loop and with injection of the sample to the capillary column (2nd cryofocusing step) created by the relatively high levels of carbon dioxide and moisture in these samples have been evaluated and minimized by optimizing the temperature of the cryogenic trap. The analytical system is sensitive and provides an accurate measurement of VOC concentration in ambient air even if the concentration is as low as 0.02 ppb by volume. The performance of this method was tested during the Northeastern New Jersey - Staten Island, Urban Air Toxics Assessment Project.